The other reasons are described in the description of each individual BIF.
Some BIFs can be used in guard tests and are marked with "Allowed in guard tests".
never fails, as the text representation of an atom can only contain characters from 0 through 255.
In a future release, the text representation of atoms can be allowed to contain any Unicode character and Use this option when receiving binaries from an untrusted source.
If so, communication with the timer service takes much longer time than if it is located locally.